1. Field of the Invention
The present invention relates to a supplemental restraint system for vehicles, more particularly to a system that can be used in combined with safety belt and be fastened-on by the driver and/or the passengers as a restraint system serving as supplemental protection from injury in case of accidental impact.
2. Description of Prior Art
Air bag has become one of the standard equipments for most cars and is intended to protect the driver and/or the passengers from injury upon accidental impact. In the beginning, only single air bag was embedded into the steering wheel. Recently, passenger air bags, side air bags and rear seat bags have also been developed and installed in suitable positions within the automobile. In the United States, protection to the lower limbs has been emphasized in recent years. This brought about the introduction of the lap air bag for protection the knees.
A leading auto company, Mercedes Benz, has announced an "X-bag Studie" wherein about seventeen air bags are installed within an experimental model. The air bags are installed under the dashboard, within the four doors, ceiling, back of front seats, under the headrest and in the front and lap portion of rear seats. In such a case, almost the entire compartment is fitted with air bags intended to provide a safer environment to the driver and passengers from the shock caused by the vehicle's possible high speed collision. However, the safety of the air bag is still a controversial issue since many drivers and/or passengers claim that their eyes and/or face have been injured by the explosive deployment of the air bag. Furthermore, there was a case reported that an infants neck was pushed broken by an inflated air bag. Because of these problems, there is still a need to improve the current air bag design.
The conventional air bag which is normally embedded in the steering wheel and the dashboard has a potential risk to the driver and passenger. Once the air bag is deployed, the explosive force of the inflated bag projects toward the face of the driver and the passenger and can possibly cause injury to them. Moreover, the conventional air bag is fixedly embedded in the steering wheel or on the dashboard wherein the relative position between the driver/passenger cannot be adjusted. If the driver/passenger has a shorter or smaller figure, or they ignore to buckle up the safety belt, they are likely to get injured on their face and eyes, due to insufficient space between their body and the air bag.
Furthermore, for cars equipped with more than two air bags, unless a sensor is installed in the passengers seat, all of the air bags would be deployed in case of collision. Once the air bags are deployed, the steering wheel, dashboard and/or other areas where the air bags are installed will be blown out leaving an unsightly hole. Consequently, the repair and replacement of the air bags, steering wheel, dashboard and/or other areas that contained air bags will be quite expensive. For example, the cost to repair the two front air bags for the Chrysler Concord is about USD3,500, which is quite a financial burden for the owner. Accordingly, the expensive cost of installing and repairing air bags will limit the prevalence of the air bag.
In order to minimize the above mentioned risk of the air bag, new car models (1997), have been incorporated with extra safety systems to serve as the reciprocator of air bag. The pre-tensioner system of the safety belt is one example. In the pre-tensioner system, an explosive package or a pre-tensioner apparatus is packed in the collar of the safety belt. Once the car collides exceeding certain speed, the explosives or the pre-tensioner apparatus will be ignited, this generates a retracting force to hold the driver/passenger back to the seat. The pre-tensioner system and safety belt help the driver/passenger remain in the seat at the time of collision which minimizes the risk of bumping into the steering wheel and/or dashboard. This also reduces the possibility of being injured by the inflated air bag even if the air bag is deployed.
Another auxiliary system is to install a sensor under the passenger seat. The sensor insures that the passenger side air bag will not be deployed in the collision if there is no passenger on the seat. This auxiliary sensor helps to reduce the cost of repairing and replacing the hole left by the deployed air bag.